Dogs Can't Talk

But they can imitate sounds:

Scientists have made some progress in their study of this important subject: They've learned why dogs, and other animals, have rather poor pronunciation and, for example, completely botch consonants. They "don't use their tongues and lips very well, and that makes it difficult for them to match many of the sounds that their human partners make," Lucas says. "Try saying 'puppy' without using your lips and tongue."